Quantum Coherence in an Exactly Solvable One-dimensional Model with Defects

TL;DR

This paper constructs an exactly solvable one-dimensional quantum model with defects using the Quantum Inverse Scattering Method, analyzing how defects affect ground state energy and flux dependence.

Contribution

It introduces a new integrable Heisenberg-XXZ model with defects involving three sites, providing exact solutions and analysis of defect effects.

Findings

Finite size corrections to ground state energy are minimal at intermediate defect strength.

Ground state wavefunction remains extended despite small energy corrections.

Dependence of energy on external flux varies with defect parameter .

Abstract

Using the Quantum Inverse Scattering Method we construct an integrable Heisenberg-XXZ-model, or equivalently a model for spinless fermions with nearest-neighbour interaction, with defects. Each defect involves three sites with a fine tuning between nearest-neighbour and next-nearest-neighbour terms. We investigate the finite size corrections to the ground state energy and its dependence on an external flux as a function of a parameter $\nu$, characterizing the strength of the defects. For intermediate values of $\nu$, both quantities become very small, although the ground state wavefunction remains extended.